It is called solenoid to coil which, by design, generates a high intensity magnetic field . This coil, cylindrical in shape, has a conducting wire that is wound in such a way that the current causes the formation of an intense magnetic field. It should be mentioned that in its etymology we find the union of two terms of Greek origin that can be translated as "tube-shaped", which is consistent with the appearance of the solenoid.
The current is circulated through the solenoid lead wire and the field is generated: the larger the coil, the more uniform the field inside. According to nucleus , the solenoid can act as electromagnet .
The solenoid is used in a valve class that is called solenoid valve . The opening and closing of these valves are produced by electrical pulses and can be controlled, in certain cases, by means of a Program .
We can find solenoids in the cars . He starter solenoid of the vehicle, when the key is turned, it is coupled to the starter motor through a axis and manages to generate the necessary movement for the motor to turn.
This solenoid, therefore, receives current when the key turns; said current begins the procedure to force the start, including actions on a piston, a pinion and the engine crankshaft. Once the engine starts to spin, the fuel reaction allows it to generate its own energy. In this way, the crankshaft rotation is no longer necessary.
It should be noted that, when the key passes from "start" to the position of "switched on", the solenoid deactivation occurs. This means that the cylindrical coil stops sending current to the motor of start .
The most prominent benefit of the use of the solenoid can be seen when performing certain experiments in the field of physics, and it is the uniformity it offers, as mentioned in previous paragraphs. On the other hand, it also has some disadvantages, such as being unable to generate a high magnetic field if you do not have a refrigeration system and high cost equipment , and that is less direct than Helmholtz coils.
The helmholtz coils On the other hand, they have a circular shape and share the same axis, as well as the same level of current that flows in a single direction, and are used in laboratory techniques that seek a magnetic field of great uniformity. In order for the central field to be as uniform as possible, the coils must be located at a distance from each other that equals their radio .
The physicist and mathematician of French origin André-Marie Ampère , who was born at the end of the 18th century and lived until the middle of the 19th century, was the first person to coin the term solenoid, and did so in the year 1820. At that time, he was working on an experiment whose main theme was the currents Circular
It is not so often that we encounter an invention so old that it continues to be relevant today, especially if we consider that its use takes place in the field of science , where constant advances make many discoveries obsolete.
The formula to perform the calculation of the magnetic field in the middle third is the following: B = mNi / L . The variables involved in this equation are the magnetic permeability (m), the number of turns (N), the circulating current (i) and the total length .
On the other hand, with these same elements it is possible to calculate the countryside magnetic ends. To give this approximation it is necessary to make a single change: multiply by two the length of the solenoid before dividing the result of the product mNi .